\\[-1.8ex] Soil Heterogeneity & $-$0.084$^{***}$ & $-$0.081$^{**}$ & $-$0.077$^{***}$ & $-$0.070$^{***}$ \\ 
  & (0.032) & (0.032) & (0.027) & (0.026) \\ 
\\[-1.8ex] 
Observations & 23,443 & 23,443 & 23,172 & 23,172 \\ 
R$^{2}$ & 0.385 & 0.391 & 0.392 & 0.407 \\ 
